Study of the in vitro activities of rifaximin and comparator agents against 536 anaerobic intestinal bacteria from the perspective of potential utility in pathology involving bowel flora.

Rifaximin, ampicillin-sulbactam, neomycin, nitazoxanide, teicoplanin, and vancomycin were tested against 536 strains of anaerobic bacteria. The overall MIC of rifaximin at which 50% of strains were inhibited was 0.25 microg/ml. Ninety percent of the strains tested were inhibited by 256 microg/ml of rifaximin or less, an activity equivalent to those of teicoplanin and vancomycin but less than those of nitazoxanide and ampicillin-sulbactam.

In vitro activities of DX-619 and four comparator agents against 376 anaerobic bacterial isolates.

The activity of DX-619 was evaluated against 376 anaerobic isolates using the reference CLSI agar dilution method. Overall, 90% of the strains were susceptible to DX-619 at < or =1 microg/ml. It was more active than the other four compounds tested except for meropenem, which showed virtually identical overall activity.

In vitro activity of telithromycin (HMR 3647) against 502 strains of anaerobic bacteria.

In a previous study, we compared HMR 3004 with azithromycin, clarithromycin, erythromycin and roxithromycin against 502 anaerobic bacteria using NCCLS-approved procedures. This report extends this study by reporting the activity of telithromycin (HMR 3647) against these strains. Telithromycin inhibited 10% of Bacteroides fragilis, 50% of other B. fragilis group organisms and 93% of other Bacteroides spp. Telithromycin inhibited all Porphyromonas spp. and 98% of Prevotella spp. Activity against Bilophila wadsworthia (85-96%) was excellent. Telithromycin was not active against the Fusobacterium mortiferum/varium group. Telithromycin inhibited 100% of Clostridium perfringens, 46-56% of Clostridium difficile and Clostridium ramosum and approximately 90% of non-spore-forming Gram-positive bacilli.

In vitro activities of MK-826 (L-749,345) against 363 strains of anaerobic bacteria.

The activity of MK-826 was compared to the activities of cefoxitin, ceftriaxone, imipenem, and meropenem against 363 gram-negative and gram-positive anaerobes by using NCCLS procedures. At least 98% of the strains were susceptible to the carbapenems. All strains of Clostridium perfringens, Fusobacterium nucleatum, Peptostreptococcus, and Sutterella wadsworthensis were susceptible to all agents tested.

In vitro activity of levofloxacin against a selected group of anaerobic bacteria isolated from skin and soft tissue infections.

The in vitro activity of levofloxacin was compared to the activities of ofloxacin, ciprofloxacin, ampicillin-sulbactam (2:1), cefoxitin, and metronidazole for a selected group of anaerobes (n = 175) isolated from skin and soft tissue infections by using the National Committee for Clinical Laboratory Standards-approved Wadsworth method. Ampicillin-sulbactam and cefoxitin inhibited 99% of the strains of this select group, levofloxacin and ofloxacin inhibited 73 and 50%, respectively, at 2 microg/ml, and ciprofloxacin inhibited 51% at 1 microg/ml. The geometric mean MIC of levofloxacin was lower than those of ofloxacin and ciprofloxacin for every group except Veillonella.

In vitro activities of trovafloxacin against 557 strains of anaerobic bacteria.

The antimicrobial activity of trovafloxacin for 557 strains of anaerobic bacteria was determined by the National Committee for Clinical Laboratory Standards-approved Wadsworth agar dilution technique. The species tested included Bacteroides fragilis (n = 91), other members of the B. fragilis group (n = 130), Campylobacter gracilis (n = 15), other Bacteroides spp. (n = 16), Prevotella spp. (n = 49), Porphyromonas spp. (n = 15), Fusobacterium spp. (n = 62), Bilophila wadsworthia (n = 24), Sutterella wadsworthensis (n = 21), Clostridium spp. (n = 61), Peptostreptococcus spp. (n = 38), and gram-positive non-spore-forming rods (n = 35). Trovafloxacin inhibited all strains of B. fragilis at < or = 0.5 microgram/ml, 99% of other B. fragilis group species at < or = 2 micrograms/ml, and 96% of all anaerobes tested at < or = 2 micrograms/ml.